User manual

SM User Manual January 2004
Software Release 4.1
Canopy™ System
Calculator
Automatically calculate
Angle of Antenna Downward Tilt
from known
Distance from Transmitter to Receiver
Elevation of Transmitter
Elevation of Receiver
Distance from transmitter to receiver (kilometers)
Elevation of transmitter (meters)
Elevation of receiver (meters)
Distance from transmitter to receiver (miles)
Elevation of transmitter (feet)
Elevation of receiver (feet)
Angle of antenna downward tilt (from metric calculation)
Angle of antenna downward tilt (from English standard calculation)
Determinants
Results
Enter Values
Read Values
Figure 19: Canopy System Calculator page for antenna downward tilt
5.3.4 Fresnel Loss
The Fresnel (pronounced fre·NEL) Zone is a theoretical three-dimensional area around the line of
sight of an antenna transmission. Objects that penetrate this area can cause the received signal
strength of the transmitted signal to fade. Out-of-phase reflections and absorption of the signal
result in signal cancellation.
An unobstructed line of sight is important, but is not the only determinant of adequate placement.
Even where the path has a clear line of sight, obstructions such as terrain, vegetation, metal roofs,
or cars may penetrate the Fresnel zone and cause signal loss. Figure 20 illustrates an ideal
Fresnel zone.
Issue 5 Page 51 of 119